Field intensity meter



Nov. 99 1948. A. ARINGER FIELD INTENSITY METER 'Filed OCT.. 24, 1945 @Zozmnoidm IN VEN TOR. ABRAHAM RINGER @www E @La f/fr/fey,

Patented Nov. 9, 1948 .FIELD `INIIENSITY l, METER IlAbraham 1Ringer,"'Eatontown, N. LJ., assignor `to ''the'f Uxiited'StatesI ff' Americavas represented by the' -Secretaryfof-'War 1 Application '10.ct0ber124, 1945, Serial No. 624,281

( Cl." r`Z50-@1) (Grantcdnnder the fact ofiMarchL-S, 11883, as

.amendcd,.April30, 1928;.;370 O.1G.'757) 256i Claims.

'factm-edi and used by tor for vthe .Governmentjfor governmentali#purposes,-'vvitliout the'zp ayment to meicfvany'royaltythereon.

`This finvention `relates fto `field`-intensity -in'dicaters, particularly tota novel indicator which can be 'used ffor '-a?djusting vrthe operating characteristics ofantennas'iwith afminimum'ofvtime and personnel.

In *adjustingfardirectional antenna, it lis :the practice "tto" place a' `neldintensity meter i in the radiationfieldof therantennaalong the desired directionrandf'then vizo-"orient the-antenna-pattern until the.meter` indicatesL the `desired directional characteristic. 'ln order that the --adjustment V'o'f the antenna be` unaiected'by the, presence l'of I-the il'eld'rintensity meter andthepovverilines connected theretogitis "desirable to place the'meter'outs'ide of 'the '.Linductionf'eld n,of the antenna, and preferably'three or, more wavelengths; away`"from"the antenna. Where vthe Wavelength is relatively l0ng,`: it'has" been f necessary to have one person adjust the. antenna iandianotherxperson to read themeter.

"It isa'principal object'of'this: invention tojirovide a novel field-intensity meter'which' indicates field intensityfby audible means.

It isla-further object ofthiseinvention to,pr,o vide-fla Vnovel field-intensity meter .in which variations infield intensity are aindicated by fvariations inipitch of an audible'li'.one-vvhichly can ,be heard at aconsiderable distance,-whereby:theopenator making the antenna adjustmentstcantfalso determine the field intensity.

In accordance with this invention, the indicator comprisesr a means to pick up the radiated wave and impress it upon a self-quenching superregenerative detector, which quenches at a rate which is dependent upon the field intensity of the input wave. The quench frequency may then be amplified and heterodyned with the output of a local oscillator to yield an audible beat frequency which is amplified and impressed upon a loud speaker, the output of which can be heard at a considerable distance by the operator While he is adjusting the directional antenna. Or, the audio output can be used to modulate a small transmitter operating on a different frequency channel and thenreceived by the operator making the antenna adjustments.

For a better understanding of the invention, together with other and further objects thereof, reference is had to the following description taken in connection with the single figure of the accom- 2 l panyingidrawingywhich shows a'block diagranro'f the'invention. l

The preferred embodiment of the inventionlnf cludes: annantenna grwhich picks up thetransmitted:wavenand'zapplies it, `through a tunable heterodyneconverter l2, to the input circuit -of'a selfFquenche-d superregenerative detector M. Sincefitcis#characteristic 0f a self-.quenching superregenerativedetector to quench itself at a rate which is dependent upon the: amplitudeof the sig-1 nal input,'fthefrequency of the quenchingpotentials. inftheroutput "of rthedetector will varyv with the field intensity. IWherethe receivedwave'isof re'latively'higlrfrequency, i. e.,"inthe l5 mc. region orfhigher,thefconvertermaybe eliminated. For

lower'frequen'ciesmse of the converter is 4desirable torchangesaid frequencies toa higher frequency, because'- kin self=quenching superregenerative de# tectors the quenching frequency as Well as the rate of change of quenching frequency are dependent upon thefrequency-ofthelsignal input.- f Hence,'to get Ya''large'-.variation in' quenchifrequency, preferably in the 4superaudible region, use of con` verter .il 2=vtof-raise1"the Efrequer-icy ofy the input is desirable. v'

"Theidetector itisalsoiprovided With a controll lr6 Aifor vcontrol-ling the #quenching "frequency-i and the limits of variation thereof by variation of the time constant rof `the usualfgrid leakA and con- ,denseriincorporated inthe detector. V"Ihe'de tectorJMfidiff'ersffrom the usualform of superrel generativerdetector in that the'outputthereof is notj'provided'with `any means to filter out the:

quench-"frequency potentials. Said quenchefrequency potentials therefore appear in the output of the detector and are amplified by a quench-frequency amplifier I8. Because of the high frequency of the Waves impressed upon the detector input, the quench-frequency of the self-quenching detector I4 is usually in the superaudible region. To convert said superaudible frequency currents to audible currents, use is made of a heterodyne converter 20 comprising a local oscillator 22, which is preferably tunable, and a mixer 24. The audio output of the mixer is amplified to any desired degree by an audio frequency amplifier 26, and then applied, through a selector switch 28, to a loud speaker 30 or to the modulation circuit of a small transmitter 32 operating in a frequency band which is considerably removed from the frequency of the antenna being tested.

This completes the description of the invention. In operation, the tunable heterodyne converter I2 converts to about 15 rnc. the antenna currents which, in one particular embodiment, range from 3 mc. to 6 mc. The superregenerative detector I4 detects the 15 mc. currents. Because of the self-quenching action of detector I 4, the quench-frequency varies with the signal strength impressed upon the input of the detector. With a 15 mc. input the quenching-frequency varies from 28 kc. to 38 kc. with variation in signal strength. then amplified at I8 and then changed by converter 20 to an audible frequency current in a range of which the limits can be controlled by adjustment of either the quench-frequency control l6 and/or frequency of local oscillator 22. The audible frequency currents are now amplified at 26 and then reproduced by loudspeaker 30 at such Volume that it is Within the hearingrange of the operator adjusting the antenna. Or, the audio currents can be used to modulate transmitter 32, the output ofwhich is picked up by the operator. It is to be understood that a frequency meter or other type of frequency-'responsive circuit may he used in place of the loud speaker.

In adjusting the eifective direction of a directional antenna, with the use of this invention, the operator moves the antenna or adjusts the antenna characteristics until the frequency of the audible note heard is either a maximum or minimum, thus indicating a maximum or a null in the field intensity, respectively.

While there has been described what is at present considered a preferred embodiment of the invention, it Will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from the invention, and it is aimed in the appended claims to cover all such changes and' modifications as fall within the true spirit and scope of the invention.

What is claimed is:

1. A field-intensity indicator for high fre quency radio Waves comprising a superregenerative detector upon the input circuit of Which said Waves are impressed, the quenching frequency of said detector varying with variation in amplitude of said radio Waves, and frequency indicator means controlled by the output of saidy detector.

2. A field-intensity indicator for high frequency radio Waves comprising a superregenerative detector upon the input circuit ofvwhich said Waves are impressed, the quenching frequency of said detector varying with variation in amplitude of said radio Waves, and frequency The quench-frequency potential is f 4 indicator means controlled by the quenchingfrequency output of said detector.

3. A field-intensity indicator for high frequency radio Waves comprising a self-quenching superregenerativedetector upon the-input circuit of which said .waves are impressed, and frequency indicator means controlled by the output of said detector.

4. A held-intensity indicator for radio Waves comprising an antenna responsive to said Waves, a heterodyne converter for converting said Waves to a higher frequency, a self-quenching superregenerative detector upon the input circuit of which said higher frequency waves are impressed, and frequency indicator means controlled by the output of said detector.

5. An aural held-intensity indicator for high frequency radio waves comprising an antenna responsive to said Waves, a self-quenching superregenerative detector upon the input circuit of which said waves are impressed, a heterodyne converter coupled to the output of said detector' to convert the quench-frequency output thereof` to a lower frequency, and acoustic frequency indicator means energized by said lower frequency.

6. An aural held-intensity indicator for radio waves comprising an antenna responsive to s aidf Waves, a tunable heterodyne converter for converting said Waves to a higher, fixed frequency, a self-quenching, unfiltered` superreg'enerative detector upon .the input circuit of .which said. xed-frequency waves are impressed, said kiixed frequency being such that the quench-frequency. is superaudible, means in said detector for con, trolling the time constant of the quenchingcir-4 cuit, a quench-frequency amplifier coupled to the output of said detector, a tunable heterodyne. converter coupled to said amplier toconvert, said quench-frequency output to an audible fref-jv quency, and acoustic frequency indicator means!` energized by said audible frequency.v n Y l i j ABRAHAM RINGER; 'REFERENCES CITED rihe following references are ofrecordfinv, le ofr this patent:

UNITED STATES PATENTS Number Name Date 1,788,078 y Ba1s1ey- Jan'. 6,'1931jf" 1,971,347 Hyland Aug. 28, 1934,.- 2,148,287 Becker Feb. 21, 1939 2,201,020 Bagno` May 14, 1940 2,393,717

Speaker Jan; 29, 1946 

